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351 Commits

Author SHA1 Message Date
Dávid Bolvanský
26599cbe3f Revert "[BPI] Improve static heuristics for integer comparisons"
This reverts commit 50c743fa713002fe4e0c76d23043e6c1f9e9fe6f. Patch will be split to smaller ones.
2020-08-17 20:44:33 +02:00
Dávid Bolvanský
7129f2d26c [BPI] Improve static heuristics for integer comparisons
Similarly as for pointers, even for integers a == b is usually false.

GCC also uses this heuristic.

Reviewed By: ebrevnov

Differential Revision: https://reviews.llvm.org/D85781
2020-08-13 19:54:27 +02:00
Dávid Bolvanský
baa55bd4d6 Revert "[BPI] Improve static heuristics for integer comparisons"
This reverts commit 44587e2f7e732604cd6340061d40ac21e7e188e5. Sanitizer tests need to be updated.
2020-08-13 14:37:40 +02:00
Dávid Bolvanský
f4c1a714d0 [BPI] Improve static heuristics for integer comparisons
Similarly as for pointers, even for integers a == b is usually false.

GCC also uses this heuristic.

Reviewed By: ebrevnov

Differential Revision: https://reviews.llvm.org/D85781
2020-08-13 14:23:58 +02:00
Alexandre Ganea
b12b3875d3 Re-Re-land: [CodeView] Add full repro to LF_BUILDINFO record
This patch adds the missing information to the LF_BUILDINFO record, which allows for rebuilding a .CPP without any external dependency but the .OBJ itself (other than the compiler).

Some external tools that we are using (Recode, Live++) are extracting the information to reproduce a build without any knowledge of the build system. The LF_BUILDINFO stores a full path to the compiler, the PWD (CWD at program startup), a relative or absolute path to the TU, and the full CC1 command line. The command line needs to be freestanding (not depend on any environment variables). In the same way, MSVC doesn't store the provided command-line, but an expanded version (somehow their equivalent of CC1) which is also freestanding.

For more information see PR36198 and D43002.

Differential Revision: https://reviews.llvm.org/D80833
2020-08-10 13:36:30 -04:00
OCHyams
9d1808f4ad [DebugInfo] Drop location ranges for variables which exist entirely outside the variable's scope
Summary:
This patch reduces file size in debug builds by dropping variable locations a
debugger user will not see.

After building the debug entity history map we loop through it. For each
variable we look at each entry. If the entry opens a location range which does
not intersect any of the variable's scope's ranges then we mark it for removal.
After visiting the entries for each variable we also mark any clobbering
entries which will no longer be referenced for removal, and then finally erase
the marked entries. This all requires the ability to query the order of
instructions, so before this runs we number them.

Tests:
Added llvm/test/DebugInfo/X86/trim-var-locs.mir

Modified llvm/test/DebugInfo/COFF/register-variables.ll
  Branch folding merges the tails of if.then and if.else into if.else. Each
  blocks' debug-locations point to different scopes so when they're merged we
  can't use either. Because of this the variable 'c' ends up with a location
  range which doesn't cover any instructions in its scope; with the patch
  applied the location range is dropped and its flag changes to IsOptimizedOut.

Modified llvm/test/DebugInfo/X86/live-debug-variables.ll
Modified llvm/test/DebugInfo/ARM/PR26163.ll
  In both tests an out of scope location is now removed. The remaining location
  covers the entire scope of the variable allowing us to emit it as a single
  location.

Reviewed By: aprantl

Differential Revision: https://reviews.llvm.org/D82129
2020-07-22 12:45:21 +01:00
Elvina Yakubova
6cd76408bf [llvm-readobj] Update tests because of changes in llvm-readobj behavior
This patch updates tests using llvm-readobj and llvm-readelf, because
soon reading from stdin will be achievable only via a '-' as described
here: https://bugs.llvm.org/show_bug.cgi?id=46400. Patch with changes to
llvm-readobj behavior is here: https://reviews.llvm.org/D83704

Differential Revision: https://reviews.llvm.org/D83912

Reviewed by: jhenderson, MaskRay, grimar
2020-07-20 10:39:04 +01:00
Craig Topper
5326734b74 [X86] Change the scheduler model for 'pentium4' to SandyBridgeModel.
I meant to do this in D83913, but missed it while updating the
feature list.

Interestingly I think this is disabling the postRA scheduler. But
it does match our default 64-bit behavior.

Reviewed By: echristo

Differential Revision: https://reviews.llvm.org/D83996
2020-07-16 22:04:29 -07:00
Craig Topper
ab11c1e42d [X86] Change the tuning settings for pentium4 to be more modern since its the default 32-bit cpu in clang
Alternative to D83897. I believe the big change here is that I removed slow unaligned memory 16

Down side that it may adversely effect tuning if someone explicitly targets -march=pentium4 and expects pentium4 tuned code. Of course pentium4 is so old our default behavior with the previous settings may not have been the best either.

Reviewed By: echristo, RKSimon

Differential Revision: https://reviews.llvm.org/D83913
2020-07-16 12:51:25 -07:00
Alexandre Ganea
705079ab21 Revert "Re-land [CodeView] Add full repro to LF_BUILDINFO record"
This reverts commit add59ecb34e3003311b7e2318b16a0ef10c76d79 and 41d2813a5faea1c18b7d329109e0287c5cd9ffea.
2020-07-10 19:46:16 -04:00
Alexandre Ganea
9a060a30d3 Re-land [CodeView] Add full repro to LF_BUILDINFO record
This patch adds some missing information to the LF_BUILDINFO which allows for rebuilding an .OBJ without any external dependency but the .OBJ itself (other than the compiler executable).

Some tools need this information to reproduce a build without any knowledge of the build system. The LF_BUILDINFO therefore stores a full path to the compiler, the PWD (which is the CWD at program startup), a relative or absolute path to the TU, and the full CC1 command line. The command line needs to be freestanding (not depend on any environment variable). In the same way, MSVC doesn't store the provided command-line, but an expanded version (somehow their equivalent of CC1) which is also freestanding.

For more information see PR36198 and D43002.

Differential Revision: https://reviews.llvm.org/D80833
2020-07-10 13:59:28 -04:00
Alexandre Ganea
9c0760ffe3 [CodeView] Revert 8374bf43634725dc02a262a77b5f940fca25938c and 403f9537924b8910ed4f741ed96c61f5e657915b
This reverts:
8374bf43634725dc02a262a77b5f940fca25938c [CodeView] Fix generated command-line expansion in LF_BUILDINFO. Fix the 'pdb' entry which was previously a null reference, now an empty string.
403f9537924b8910ed4f741ed96c61f5e657915b [CodeView] Add full repro to LF_BUILDINFO record

This is causing the lld/test/COFF/pdb-relative-source-lines.test to fail: http://lab.llvm.org:8011/builders/lld-x86_64-win/builds/1096/steps/test-check-all/logs/FAIL%3A%20lld%3A%3Apdb-relative-source-lines.test
And clang/test/CodeGen/debug-info-codeview-buildinfo.c fails as well: http://lab.llvm.org:8011/builders/clang-s390x-linux/builds/33346/steps/ninja%20check%201/logs/FAIL%3A%20Clang%3A%3Adebug-info-codeview-buildinfo.c
2020-06-18 16:18:46 -04:00
Alexandre Ganea
4f9af6d5f5 [CodeView] Fix generated command-line expansion in LF_BUILDINFO. Fix the 'pdb' entry which was previously a null reference, now an empty string.
Previously, the DIA SDK didn't like the empty reference in the 'pdb' entry.
2020-06-18 10:07:30 -04:00
Jon Roelofs
d0f0991d73 Revert "[llvm][test] Add COM: directives before colon-less non-CHECKs in comments. NFC"
This reverts commit 183d6af081899973f00fc24aeafcfc32de732f02.

Revert pending further consensus building: https://reviews.llvm.org/D79963#2050521
2020-05-22 05:36:15 -06:00
Jon Roelofs
aae486e5a4 [llvm][test] Add COM: directives before colon-less non-CHECKs in comments. NFC
Differential Revision: https://reviews.llvm.org/D79963
2020-05-21 09:29:27 -06:00
Reid Kleckner
4fb2315347 Re-land [Debug][CodeView] Emit fully qualified names for globals
This reverts commit 525a591f0f48b9d54018bf5245f2abee09c9c1c8.

Fixed an issue with pointers to members based on typedefs. In this case,
LLVM would emit a second UDT. I fixed it by not passing the class type
to getTypeIndex when the base type is not a function type. lowerType
only uses the class type for direct function types. This suggests if we
have a PMF with a function typedef, there may be an issue, but that can
be solved separately.
2020-05-18 17:31:00 -07:00
Hans Wennborg
9a60071199 Revert 76c5f277f2 "Re-land [Debug][CodeView] Emit fully qualified names for globals"
> Before this patch, S_[L|G][THREAD32|DATA32] records were emitted with a simple name, not the fully qualified name (namespace + class scope).
>
> Differential Revision: https://reviews.llvm.org/D79447

This causes asserts in Chromium builds:

CodeViewDebug.cpp:2997: void llvm::CodeViewDebug::emitDebugInfoForUDTs(const std::vector<std::pair<std::string, const DIType *>> &):
Assertion `OriginalSize == UDTs.size()' failed.

I will follow up on the Phabricator issue.
2020-05-18 11:26:30 +02:00
Alexandre Ganea
a17891d60b Re-land [Debug][CodeView] Emit fully qualified names for globals
Before this patch, S_[L|G][THREAD32|DATA32] records were emitted with a simple name, not the fully qualified name (namespace + class scope).

Differential Revision: https://reviews.llvm.org/D79447
2020-05-15 10:37:09 -04:00
Alexandre Ganea
83e616ec37 Revert "[Debug][CodeView] Emit fully qualified names for globals"
This reverts commit 06591b6d191ad3582d21a801cbaf56b36714cae7.
2020-05-06 15:23:58 -04:00
Alexandre Ganea
13e60df049 [Debug][CodeView] Emit fully qualified names for globals
Emit S_[L|G][THREAD32|DATA32] records with a fully qualified name (namespace + class scope).

Differential Revision: https://reviews.llvm.org/D79447
2020-05-06 09:12:00 -04:00
Alexandre Ganea
730dc93e22 [DebugInfo][CodeView] Include namespace into emitted globals
Before this patch, global variables didn't have their namespace prepended in the Codeview debug symbol stream. This prevented Visual Studio from displaying them in the debugger (they appeared as 'unspecified error')

Differential Revision: https://reviews.llvm.org/D79028
2020-05-04 13:59:36 -04:00
Amy Huang
995a26bf12 Reland "[codeview] Reference types in type parent scopes"
Summary:
Original description (https://reviews.llvm/org/D69924)
Without this change, when a nested tag type of any kind (enum, class,
struct, union) is used as a variable type, it is emitted without
emitting the parent type. In CodeView, parent types point to their inner
types, and inner types do not point back to their parents. We already
walk over all of the parent scopes to build the fully qualified name.
This change simply requests their type indices as we go along to enusre
they are all emitted.

Now, while walking over the parent scopes, add the types to
DeferredCompleteTypes, since they might already be in the process of
being emitted.

Fixes PR43905

Reviewers: rnk, amccarth

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D78249
2020-04-16 12:08:52 -07:00
Fangrui Song
1c1cc1c5ed [test] llvm/test/: change llvm-objdump single-dash long options to double-dash options
As announced here: http://lists.llvm.org/pipermail/llvm-dev/2019-April/131786.html

Grouped option syntax (POSIX Utility Conventions) does not play well with -long-option
A subsequent change will reject -long-option.
2020-03-15 17:46:23 -07:00
Amy Huang
84aaa5f928 [DebugInfo] Fix for adding "returns cxx udt" option to functions in CodeView.
Summary:
This change checks for the return type in the frontend and adds a flag
to the DISubroutineType to indicate that the option should be added in
CodeViewDebug.

Previously function types sometimes appeared twice in the PDB: once with
"returns cxx udt" and once without.
See https://bugs.llvm.org/show_bug.cgi?id=44785.

Reviewers: rnk, asmith

Subscribers: hiraditya, cfe-commits, llvm-commits

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D75215
2020-03-03 14:00:08 -08:00
Yuanfang Chen
dd53274771 Revert "Revert "Reland "[Support] make report_fatal_error abort instead of exit"""
This reverts commit 80a34ae31125aa46dcad47162ba45b152aed968d with fixes.

Previously, since bots turning on EXPENSIVE_CHECKS are essentially turning on
MachineVerifierPass by default on X86 and the fact that
inline-asm-avx-v-constraint-32bit.ll and inline-asm-avx512vl-v-constraint-32bit.ll
are not expected to generate functioning machine code, this would go
down to `report_fatal_error` in MachineVerifierPass. Here passing
`-verify-machineinstrs=0` to make the intent explicit.
2020-02-13 10:16:06 -08:00
Yuanfang Chen
2dbac841f9 Revert "Revert "Revert "Reland "[Support] make report_fatal_error abort instead of exit""""
This reverts commit bb51d243308dbcc9a8c73180ae7b9e47b98e68fb.
2020-02-13 10:08:05 -08:00
Yuanfang Chen
93e82c22ef Revert "Revert "Reland "[Support] make report_fatal_error abort instead of exit"""
This reverts commit 80a34ae31125aa46dcad47162ba45b152aed968d with fixes.

On bots llvm-clang-x86_64-expensive-checks-ubuntu and
llvm-clang-x86_64-expensive-checks-debian only,
llc returns 0 for these two tests unexpectedly. I tweaked the RUN line a little
bit in the hope that LIT is the culprit since this change is not in the
codepath these tests are testing.
llvm\test\CodeGen\X86\inline-asm-avx-v-constraint-32bit.ll
llvm\test\CodeGen\X86\inline-asm-avx512vl-v-constraint-32bit.ll
2020-02-13 10:02:53 -08:00
Yuanfang Chen
c7fb4c55c4 Revert "Reland "[Support] make report_fatal_error abort instead of exit""
This reverts commit rGcd5b308b828e, rGcd5b308b828e, rG8cedf0e2994c.

There are issues to be investigated for polly bots and bots turning on
EXPENSIVE_CHECKS.
2020-02-11 20:41:53 -08:00
Yuanfang Chen
83a2f3c1ba Reland "[Support] make report_fatal_error abort instead of exit"
Summary:
Reland D67847 after D73742 is committed. Replace `sys::Process::Exit(1)`
with `abort` in `report_fatal_error`.

After this patch, for tools turning on `CrashRecoveryContext`,
crash handler installed by `CrashRecoveryContext` is called unless
they installed a non-returning handler using `llvm::install_fatal_error_handler`
like `cc1_main` currently does.

Reviewers: rnk, MaskRay, aganea, hans, espindola, jhenderson

Subscribers: jholewinski, qcolombet, dschuff, jyknight, emaste, sdardis, nemanjai, jvesely, nhaehnle, sbc100, jgravelle-google, hiraditya, aheejin, kbarton, fedor.sergeev, asb, rbar, johnrusso, simoncook, sabuasal, niosHD, jrtc27, zzheng, edward-jones, atanasyan, steven_wu, rogfer01, MartinMosbeck, brucehoult, the_o, dexonsmith, PkmX, rupprecht, jocewei, jsji, Jim, dmgreen, lenary, s.egerton, pzheng, sameer.abuasal, apazos, luismarques, kerbowa, cfe-commits, llvm-commits

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D74456
2020-02-11 18:20:40 -08:00
Jeremy Morse
8e9ec7843f Revert "[DebugInfo] Remove some users of DBG_VALUEs IsIndirect field"
This reverts commit ed29dbaafa49bb8c9039a35f768244c394411fea.

I'm backing out D68945, which as the discussion for D73526 shows, doesn't
seem to handle the -O0 path through the codegen backend correctly. I'll
reland the patch when a fix is worked out, apologies for all the churn.
The two parent commits are part of this revert too.

Conflicts:
	llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
	llvm/test/DebugInfo/X86/dbg-addr-dse.ll

SelectionDAGBuilder conflict is due to a nearby change in e39e2b4a79c6
that's technically unrelated. dbg-addr-dse.ll conflicted because
41206b61e30c (legitimately) changes the order of two lines.

There are further modifications to dbg-value-func-arg.ll: it landed after
the patch being reverted, and I've converted indirection to be represented
by the isIndirect field rather than DW_OP_deref.
2020-02-06 14:41:40 +00:00
Jeremy Morse
7fa348477a Revert "[SafeStack][DebugInfo] Insert DW_OP_deref in correct location"
This reverts commit 2d3174c4df6b5f4131346828d0a31675d80d6e2b.

The overall solution for this problem is reverting D68945, which wasn't
handling the -O0 path through the codegen backend correctly. See:
discussion in D73526.
2020-02-06 14:41:39 +00:00
Leonard Chan
0458fa3960 [SafeStack][DebugInfo] Insert DW_OP_deref in correct location
This patch addresses the issue found in https://bugs.llvm.org/show_bug.cgi?id=44585
where a DW_OP_deref was placed at the end of a dwarf expression, resulting in corrupt
symbols when debugging.

This is an attempt to reland with a few fixes for buildbot since I
haven't merged from master in a bit.

Differential Revision: https://reviews.llvm.org/D73526
2020-01-30 17:09:42 -08:00
Leonard Chan
383dbddb2a Revert "[SafeStack][DebugInfo] Insert DW_OP_deref in correct location"
This reverts commit fff6a1b0f1fe57b46379001db75952d2a06eab1f.

This was breaking a bunch of buildbots.
2020-01-30 16:18:41 -08:00
Leonard Chan
4199a00ff4 [SafeStack][DebugInfo] Insert DW_OP_deref in correct location
This patch addresses the issue found in https://bugs.llvm.org/show_bug.cgi?id=44585
where a DW_OP_deref was placed at the end of a dwarf expression, resulting in
corrupt symbols when debugging.

Differential Revision: https://reviews.llvm.org/D73526
2020-01-30 15:58:37 -08:00
Jonathan Roelofs
a7b7627d67 [llvm] Fix broken cases of 'CHECK[^:]*$' in tests 2020-01-28 09:52:59 -07:00
Yuanfang Chen
b1c09bbef0 Revert "[Support] make report_fatal_error abort instead of exit"
This reverts commit 647c3f4e47de8a850ffcaa897db68702d8d2459a.

Got bots failure from sanitizer-windows and maybe others.
2020-01-15 17:52:25 -08:00
Yuanfang Chen
725cd0da61 [Support] make report_fatal_error abort instead of exit
Summary:
This patch could be treated as a rebase of D33960. It also fixes PR35547.
A fix for `llvm/test/Other/close-stderr.ll` is proposed in D68164. Seems
the consensus is that the test is passing by chance and I'm not
sure how important it is for us. So it is removed like in D33960 for now.
The rest of the test fixes are just adding `--crash` flag to `not` tool.

** The reason it fixes PR35547 is

`exit` does cleanup including calling class destructor whereas `abort`
does not do any cleanup. In multithreading environment such as ThinLTO or JIT,
threads may share states which mostly are ManagedStatic<>. If faulting thread
tearing down a class when another thread is using it, there are chances of
memory corruption. This is bad 1. It will stop error reporting like pretty
stack printer; 2. The memory corruption is distracting and nondeterministic in
terms of error message, and corruption type (depending one the timing, it
could be double free, heap free after use, etc.).

Reviewers: rnk, chandlerc, zturner, sepavloff, MaskRay, espindola

Reviewed By: rnk, MaskRay

Subscribers: wuzish, jholewinski, qcolombet, dschuff, jyknight, emaste, sdardis, nemanjai, jvesely, nhaehnle, sbc100, arichardson, jgravelle-google, aheejin, kbarton, fedor.sergeev, asb, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, jrtc27, zzheng, edward-jones, atanasyan, rogfer01, MartinMosbeck, brucehoult, the_o, PkmX, jocewei, jsji, lenary, s.egerton, pzheng, cfe-commits, MaskRay, filcab, davide, MatzeB, mehdi_amini, hiraditya, steven_wu, dexonsmith, rupprecht, seiya, llvm-commits

Tags: #llvm, #clang

Differential Revision: https://reviews.llvm.org/D67847
2020-01-15 17:05:13 -08:00
Matt Arsenault
2346ede1ad llc: Change behavior of -mcpu with existing attribute
Don't overwrite existing target-cpu attributes.

I've often found the replacement behavior annoying, and this is
inconsistent with how the fast math command line flags interact with
the function attributes.

Does not yet change target-features, since I think that should behave
as a concatenation.
2020-01-07 10:10:25 -05:00
Fangrui Song
2d0a36fd96 Migrate function attribute "no-frame-pointer-elim"="false" to "frame-pointer"="none" as cleanups after D56351 2019-12-24 16:27:51 -08:00
Fangrui Song
148dd94d20 Migrate function attribute "no-frame-pointer-elim-non-leaf" to "frame-pointer"="non-leaf" as cleanups after D56351 2019-12-24 16:05:15 -08:00
Fangrui Song
d9c5df08b1 Migrate function attribute "no-frame-pointer-elim" to "frame-pointer"="all" as cleanups after D56351 2019-12-24 15:57:33 -08:00
Tom Weaver
6bf5a34797 [OPT-DBG] Teach DbgEntityHistoryCalculator about meta-instructions.
The calculator was considering instructions such as KILLs as clobbers
of a physical address. This is wrong as meta instructions such as KILLs
produce no output in the final program and thus don't clobber or change
any physical location's value. As a result they're safe to ignore whilst
calculating location list ranges.

reviewers: aprantl, vsk

diff revision: https://reviews.llvm.org/D70497

fixes: https://bugs.llvm.org/show_bug.cgi?id=38753
2019-12-20 14:03:34 +00:00
Jeremy Morse
e640a69d80 [DebugInfo] Nerf placeDbgValues, with prejudice
CodeGenPrepare::placeDebugValues moves variable location intrinsics to be
immediately after the Value they refer to. This makes tracking of locations
very easy; but it changes the order in which assignments appear to the
debugger, from the source programs order to the order in which the
optimised program computes values. This then leads to PR43986 and PR38754,
where variable locations that were in a conditional block are made
unconditional, which is highly misleading.

This patch adjusts placeDbgValues to only re-order variable location
intrinsics if they use a Value before it is defined, significantly reducing
the damage that it does. This is still not 100% safe, but the rest of
CodeGenPrepare needs polishing to correctly update debug info when
optimisations are performed to fully fix this.

This will probably break downstream debuginfo tests -- if the
instruction-stream position of variable location changes isn't the focus of
the test, an easy fix should be to manually apply placeDbgValues' behaviour
to the failing tests, moving dbg.value intrinsics next to SSA variable
definitions thus:

  %foo = inst1
  %bar = ...
  %baz = ...
  void call @llvm.dbg.value(metadata i32 %foo, ...

to

  %foo = inst1
  void call @llvm.dbg.value(metadata i32 %foo, ...
  %bar = ...
  %baz = ...

This should return your test to exercising whatever it was testing before.

Differential Revision: https://reviews.llvm.org/D58453
2019-12-09 12:52:10 +00:00
Hans Wennborg
b80c4b7b9d Revert d91ed80 "[codeview] Reference types in type parent scopes"
This triggered asserts in the Chromium build, see https://crbug.com/1022729 for
details and reproducer.

> Without this change, when a nested tag type of any kind (enum, class,
> struct, union) is used as a variable type, it is emitted without
> emitting the parent type. In CodeView, parent types point to their inner
> types, and inner types do not point back to their parents. We already
> walk over all of the parent scopes to build the fully qualified name.
> This change simply requests their type indices as we go along to enusre
> they are all emitted.
>
> Fixes PR43905
>
> Reviewers: akhuang, amccarth
>
> Differential Revision: https://reviews.llvm.org/D69924
2019-11-08 11:30:33 +01:00
Reid Kleckner
643e2e3d68 [codeview] Reference types in type parent scopes
Without this change, when a nested tag type of any kind (enum, class,
struct, union) is used as a variable type, it is emitted without
emitting the parent type. In CodeView, parent types point to their inner
types, and inner types do not point back to their parents. We already
walk over all of the parent scopes to build the fully qualified name.
This change simply requests their type indices as we go along to enusre
they are all emitted.

Fixes PR43905

Reviewers: akhuang, amccarth

Differential Revision: https://reviews.llvm.org/D69924
2019-11-07 13:58:01 -08:00
Jeremy Morse
066460043d [DebugInfo] Remove some users of DBG_VALUEs IsIndirect field
This patch kills off a significant user of the "IsIndirect" field of
DBG_VALUE machine insts. Brought up in in PR41675, IsIndirect is
techncally redundant as it can be expressed by the DIExpression of a
DBG_VALUE inst, and it isn't helpful to have two ways of expressing
things.

Rather than setting IsIndirect, have DBG_VALUE creators add an extra deref
to the insts DIExpression. There should now be no appearences of
IsIndirect=True from isel down to LiveDebugVariables / VirtRegRewriter,
which is ensured by an assertion in LDVImpl::handleDebugValue. This means
we also get to delete the IsIndirect handling in LiveDebugVariables. Tests
can be upgraded by for example swapping the following IsIndirect=True
DBG_VALUE:

  DBG_VALUE $somereg, 0, !123, !DIExpression(DW_OP_foo)

With one where the indirection is in the DIExpression, by _appending_
a deref:

  DBG_VALUE $somereg, $noreg, !123, !DIExpression(DW_OP_foo, DW_OP_deref)

Which both mean the same thing. 

Most of the test changes in this patch are updates of that form; also some
changes in how the textual assembly printer handles these insts.

Differential Revision: https://reviews.llvm.org/D68945

llvm-svn: 374877
2019-10-15 10:46:24 +00:00
Reid Kleckner
ff93e765b6 [codeview] Try to avoid emitting .cv_loc with line zero
Summary:
Visual Studio doesn't like it while stepping. It kicks you out of the
source view of the file being stepped through and tries to fall back to
the disassembly view.

Fixes PR43530

The fix is incomplete, because it's possible to have a basic block with
no source locations at all. In this case, we don't emit a .cv_loc, but
that will result in wrong stepping behavior in the debugger if the
layout predecessor of the location-less BB has an unrelated source
location. We could try harder to find a valid location that dominates or
post-dominates the current BB, but in general it's a dataflow problem,
and one still might not exist. I left a FIXME about this.

As an alternative, we might want to consider having the middle-end check
if its emitting codeview and get it to stop using line zero.

Reviewers: akhuang

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D68747

llvm-svn: 374267
2019-10-10 01:06:01 +00:00
Reid Kleckner
1d13d635fc [Windows] Replace TrapUnreachable with an int3 insertion pass
This is an alternative to D66980, which was reverted. Instead of
inserting a pseudo instruction that optionally expands to nothing, add a
pass that inserts int3 when appropriate after basic block layout.

Reviewers: hans

Differential Revision: https://reviews.llvm.org/D67201

llvm-svn: 371466
2019-09-09 23:04:25 +00:00
Reid Kleckner
3367dfc8ec Revert [Windows] Disable TrapUnreachable for Win64, add SEH_NoReturn
This reverts r370525 (git commit 0bb1630685fba255fa93def92603f064c2ffd203)
Also reverts r370543 (git commit 185ddc08eed6542781040b8499ef7ad15c8ae9f4)

The approach I took only works for functions marked `noreturn`. In
general, a call that is not known to be noreturn may be followed by
unreachable for other reasons. For example, there could be multiple call
sites to a function that throws sometimes, and at some call sites, it is
known to always throw, so it is followed by unreachable. We need to
insert an `int3` in these cases to pacify the Windows unwinder.

I think this probably deserves its own standalone, Win64-only fixup pass
that runs after block placement. Implementing that will take some time,
so let's revert to TrapUnreachable in the mean time.

llvm-svn: 370829
2019-09-03 22:27:27 +00:00
Reid Kleckner
e996333540 [Windows] Disable TrapUnreachable for Win64, add SEH_NoReturn
Users have complained llvm.trap produce two ud2 instructions on Win64,
one for the trap, and one for unreachable. This change fixes that.

TrapUnreachable was added and enabled for Win64 in r206684 (April 2014)
to avoid poorly understood issues with the Windows unwinder.

There seem to be two major things in play:
- the unwinder
- C++ EH, _CxxFrameHandler3 & co

The unwinder disassembles forward from the return address to scan for
epilogues. Inserting a ud2 had the effect of stopping the unwinder, and
ensuring that it ran the EH personality function for the current frame.
However, it's not clear what the unwinder does when the return address
happens to be the last address of one function and the first address of
the next function.

The Visual C++ EH personality, _CxxFrameHandler3, needs to figure out
what the current EH state number is. It does this by consulting the
ip2state table, which maps from PC to state number. This seems to go
wrong when the return address is the last PC of the function or catch
funclet.

I'm not sure precisely which system is involved here, but in order to
address these real or hypothetical problems, I believe it is enough to
insert int3 after a call site if it would otherwise be the last
instruction in a function or funclet.  I was able to reproduce some
similar problems locally by arranging for a noreturn call to appear at
the end of a catch block immediately before an unrelated function, and I
confirmed that the problems go away when an extra trailing int3
instruction is added.

MSVC inserts int3 after every noreturn function call, but I believe it's
only necessary to do it if the call would be the last instruction. This
change inserts a pseudo instruction that expands to int3 if it is in the
last basic block of a function or funclet. I did what I could to run the
Microsoft compiler EH tests, and the ones I was able to run showed no
behavior difference before or after this change.

Differential Revision: https://reviews.llvm.org/D66980

llvm-svn: 370525
2019-08-30 20:46:39 +00:00